Follow-up Comment #2, bug #22040 (project freeciv):
When forming an alliance with an AI, I have noticed so many triremes to create
temporary bridges. Game asks permission to transfer between triremes from a
worker agent. My workers sometimes travel 20 squares across AI triremes to
arrive at a nearby continent. It's very much like ants in a tree. Very similar
as described by the "Ant" worker AI used by telecoms for load balancing
hardware (Traveling Salesmen Problem, etc).